#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <assert.h>
#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <cstdlib>
#define BUF_SIZE 512

int main(int argc, char **argv)
{
    if (argc <= 2)
    {
        printf("usage:%s ip_address port_number send_bufer_size\n", basename(argv[0]));
        return 1;
    }
    const char *ip = argv[1];
    int port = atoi(argv[2]);
    struct sockaddr_in server_address;
    bzero(&server_address, sizeof(server_address));
    server_address.sin_family = AF_INET;
    inet_pton(AF_INET, ip, &server_address.sin_addr);
    server_address.sin_port = htons(port);
    int sock = socket(AF_INET, SOCK_STREAM, 0);
    assert(sock >= 0);
    int sendbuf = atoi(argv[3]);
    int len = sizeof(sendbuf);
    setsockopt(sock, SOL_SOCKET, SO_SNDBUF, &sendbuf, sizeof(sendbuf));
    getsockopt(sock, SOL_SOCKET, SO_SNDBUF, &sendbuf, (socklen_t *)&len);
    printf("the tcp send buffer size after setting is%d\n", sendbuf);
    if (connect(sock, (sockaddr *)&server_address, sizeof(server_address)) != -1)
    {
        char buffer[BUF_SIZE];
        memset(buffer, 'a', BUF_SIZE);
        send(sock, buffer, BUF_SIZE, 0);
    }
    close(sock);
    return 0;
}